Dsl system

ABSTRACT

Methods, techniques, computer program products, apparatus, devices, etc., used in connection with DSL Management Interfaces, significantly improve the management capabilities of a DSL network and/or improve testing relating to DSL equipment and services by permitting better control and operation of a DSL system, including implementation of timestamping for more accurate measurement, monitoring and control of a system. Timestamping further allows customized data collection techniques, where a DSL line can be measured or monitored at intervals whose frequency depends on the line&#39;s stability. Moreover, data parameter read and control parameter write operations are presented in conjunction with the use of timestamping. Also, control and operation of a DSL system is enhanced by implementing bit-loading that minimizes, eliminates or otherwise mitigates the amount by which the SNR margin per tone exceeds a maximum SNR margin quantity, where such bit-loading can be selected through an appropriate interface.

CLAIM OF PRIORITY

The present application is a continuation of, and claims the benefit ofpriority of U.S. patent application Ser. No. 13/214,598 (Attorney DocketNo. 8241P029D), filed Aug. 22, 2011, entitled DSL SYSTEM; which is adivisional of, and claims the benefit of priority of U.S. patentapplication Ser. No. 12/089,044 (Attorney Docket No. 8241P029) filed onOct. 3, 2006, entitled DSL SYSTEM; which in turn, claims the benefit ofpriority to PCT Patent Application No. PCT/US2006/038605 (AttorneyDocket No. 8241P029PCT) filed on Oct. 3, 2006, entitled DSL SYSTEM;which claims the benefit of priority to U.S. Provisional No. 60/723,415(Attorney Docket No. 8241P029Z) filed on Oct. 4, 2005, entitled DSLSYSTEM; and which further claims the benefit of priority to U.S.Provisional No. 60/839,093 (Attorney Docket No. 8241P029Z2) filed onAug. 21, 2006, entitled DSL SYSTEM; each of which are hereinincorporated by reference.

The present application is related to the following: U.S. Ser. No.10/893,826 (Atty. Docket No. 8241P004) filed 19 Jul. 2004, entitledADAPTIVE MARGIN AND BAND CONTROL, and International Application SerialNo. PCT/US2006/026796 (Atty. Docket No. 8241P033PCT) filed 8 Jul. 2006,entitled ADAPTIVE MARGIN AND BAND CONTROL.

FIELD OF THE INVENTION

This invention relates generally to methods, systems and apparatus formanaging digital communications systems. More specifically, thisinvention relates to managing a DSL system and/or a DSL device such as amodem, DSLAM or other component in a DSL system or the like.

DESCRIPTION OF RELATED ART

Digital subscriber line (DSL) technologies provide potentially largebandwidth for digital communication over existing telephone subscriberlines (referred to as loops and/or the copper plant). Telephonesubscriber lines can provide this bandwidth despite their originaldesign for only voice-band analog communication. In particular,asymmetric DSL (ADSL) can adjust to the characteristics of thesubscriber line by using a discrete multitone (DMT) line code thatassigns a number of bits to each tone (or sub-carrier), which can beadjusted to channel conditions as determined during training andinitialization of the modems (typically transceivers that function asboth transmitters and receivers) at each end of the subscriber line.

Systems, methods and techniques that improve operation in communicationsystems such as DSL systems would represent a significant advancement inthe art. In particular, improving the level and types of data availableand controllable in such communication systems would represent aconsiderable advancement in the field.

SUMMARY

Embodiments of the present invention, used in connection with DSLManagement Interfaces, significantly improve the management capabilitiesof a DSL network and/or improve testing relating to DSL equipment andservices. Such embodiments utilize improved methods, techniques,computer program products, apparatus, devices, etc. to permit bettercontrol and operation of a DSL system, including implementation oftimestamping for more accurate measurement, monitoring and control of asystem. The implementation of timestamping further allows customizeddata collection techniques, where a DSL line can be measured ormonitored at intervals whose frequency depends on the line's stability.Additional embodiments for data parameter read and control parameterwrite operations are presented in conjunction with the use oftimestamping. Also, control and operation of a DSL system is enhanced byimplementing bit-loading that minimizes, eliminates or otherwisemitigates the amount by which the SNR margin per tone exceeds a maximumSNR margin quantity, where such bit-loading can be selected through anappropriate interface.

Further details and advantages of the invention are provided in thefollowing Detailed Description and the associated Figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be readily understood by the followingdetailed description in conjunction with the accompanying drawings,wherein like reference numerals designate like structural elements, andin which:

FIG. 1 is a reference model diagram from the ITU-T G.997.1 standard.

FIG. 2 is a positioning diagram from the DSL Forum TR-069 technicalreport.

FIG. 3 is an augmented DSL system that uses the reference model of FIG.1 as a basis.

FIG. 4 is an augmented DSL system that uses the positioning diagram fromthe TR-069 report as a basis.

FIG. 5A is a schematic diagram illustrating generic, exemplary DSLdeployment.

FIG. 5B is a DSL system including a DSL optimizer according to oneembodiment of the present invention.

FIG. 6A is a controller and DSL system implementing one or moreembodiments of the present invention.

FIG. 6B is a DSL optimizer and DSL system implementing one or moreembodiments of the present invention.

FIG. 7A illustrates interfaces between a DSL Management Entity and aDSLAM, and between a DSL Management Entity and a DSL CPE modem.

FIG. 7B illustrates interfaces between a DSL Management Entity and aDSLAM, and between a DSL Management Entity and a DSL CPE modem.

FIG. 8A shows a packet including a timestamp.

FIG. 8B shows data and/or control parameters associated with anidentical timestamp grouped together in a single packet to betransferred over a DSL Management interface.

FIG. 8C shows an operational parameter associated with a time marker ina packet.

FIG. 9 is an exemplary lab DSL system.

FIG. 10A illustrates operation of a DSL lab and/or field system (and/ora computer program product implementing such methods) that includestimestamping used in connection with one or more operational parametersaccording to one or more embodiments of the present invention.

FIG. 10B illustrates operation of a DSL lab and/or field system (and/ora computer program product implementing such methods) that includes aobtaining a timestamp using coordinating or synchronizing communicationsbetween components in a DSL system according to one or more embodimentsof the present invention.

FIG. 11 illustrates adaptive data collection in a DSL loop according toone or more embodiments of the present invention.

FIG. 12 illustrates adaptive data collection in a DSL loop according toone or more embodiments of the present invention.

FIG. 13 illustrates control of a DSL system according to one or moreembodiments of the present invention.

FIG. 14 illustrates data collection from a DSL system according to oneor more embodiments of the present invention.

FIG. 15 illustrates operation of a DSL system including selection of abit loading sub-method according to one or more embodiments of thepresent invention.

FIG. 16A illustrates a DSL system attempting to comply with a per tonemaximum SNR margin requirement during initialization according to one ormore embodiments of the present invention.

FIG. 16B illustrates a DSL system attempting to comply with a MAXSNRMrequirement during SHOWTIME according to one or more embodiments of thepresent invention.

FIG. 17 is a block diagram of a typical computer system suitable forimplementing embodiments of the present invention.

DETAILED DESCRIPTION

The following detailed description of the invention will refer to one ormore embodiments of the invention, but is not limited to suchembodiments. Rather, the detailed description is intended only to beillustrative. Those skilled in the art will readily appreciate that thedetailed description given herein with respect to the Figures isprovided for explanatory purposes as the invention extends beyond theselimited embodiments.

As described in more detail below, a controller, such as a DSLmanagement entity, DSL optimizer, dynamic spectrum management center(DSM Center), Spectrum Management Center (SMC), a “smart” modem, controlsoftware/hardware and/or computer system can be used to collect andanalyze the operational data and/or performance parameter values asdescribed in connection with the various embodiments of the presentinvention. The controller and/or other components can be acomputer-implemented device or combination of devices. In someembodiments, the controller is in a location remote from the modems. Inother cases, the controller may be collocated with one of or both of themodems as equipment directly connected to a modem, DSLAM or othercommunication system device, thus creating a “smart” modem. The phrases“coupled to” and “connected to” and the like are used herein to describea connection between two elements and/or components and are intended tomean coupled either directly together, or indirectly, for example viaone or more intervening elements or via a wireless connection, whereappropriate.

Embodiments of the present invention can be used in ordinary DSL systemsand in augmented DSL systems, as described herein and/or as suggested tothose skilled in the art by the disclosure herein. Two well knownsystems in which the present invention can be used are shown in FIGS. 1and 2. FIG. 1 is a reference model diagram from the ITU-T G.997.1standard, which is well known to those skilled in the art. FIG. 2 is apositioning diagram from the DSL Forum TR-069 technical report, alsowell known to those skilled in the art. Because these systems are wellknown and understood in the art, no further detailed explanation ofFIGS. 1 and 2 is provided, except in connection with the explanation ofthe present invention.

FIG. 1 shows the reference model system according to the G.997.1standard (sometimes also called “G.ploam”), in which embodiments of thepresent invention can be implemented. This model applies to all ADSLsystems meeting the various standards that may or may not includesplitters, such as ADSL1 (G.992.1), ADSL-Lite (G.992.2), ADSL2(G.992.3), ADSL2-Lite (G.992.4), ADSL2+(G.992.5), VDSL1 (G.993.1) andother G.993.x emerging VDSL standards, as well as the G.991.1 andG.991.2 SHDSL standards, all with and without bonding. This model iswell known to those skilled in the art.

The G.997.1 standard specifies the physical-layer management for DSLtransmission systems based on the clear embedded operation channel (EOC)defined in G.997.1 and use of indicator bits and EOC messages defined inG.99x standards. Moreover, G.997.1 specifies network-management-elementscontent for configuration, fault and performance management. Inperforming these functions, the system utilizes a variety of operationaldata that are available at and can be collected from an access node(AN). The DSL Forum's TR-069 report also lists the MIB and how it mightbe accessed.

In FIG. 1, customers' terminal equipment 110 is coupled to a homenetwork 112, which in turn is coupled to a network termination unit (NT)120. In the case of an ADSL system, NT 120 includes an ATU-R 122 (forexample, a modem, also referred to as a transceiver in some cases,defined by one of the ADSL standards) or any other suitable networktermination modem, transceiver or other communication unit. In the caseof a VDSL system, the naming changes from ATU-R to VTU-R. In order togenerally describe such a module, the naming of xTU-R is used in someinstances. Each modem can be identified, for example, by manufacturerand model number. As will be appreciated by those skilled in the art andas described herein, each modem interacts with the communication systemto which it is connected and may generate operational data as a resultof the modem's performance in the communication system.

NT 120 also includes a management entity (ME) 124. ME 124 can be anysuitable hardware device, such as a microprocessor, microcontroller, orcircuit state machine in firmware or hardware, capable of performing asrequired by any applicable standards and/or other criteria. ME 124collects and stores performance data in its MIB, which is a database ofinformation maintained by each ME, and which can be accessed via networkmanagement protocols such as SNMP (Simple Network Management Protocol),an administration protocol used to gather information from a networkdevice to provide to an administrator console/program or via TL1commands, TL1 being a long-established command language used to programresponses and commands between telecommunication network elements.

Each ATU-R in a system is coupled to an ATU-C in a CO or other centrallocation. In FIG. 1, ATU-C 142 is located at an access node (AN) 140 ina CO 146. AN 140 may be a DSL system component, such as a DSLAM or thelike, as will be appreciated by those skilled in the art. In the case ofa VDSL system, the naming changes from ATU-C to VTU-O. In order togenerally describe such a module, the naming of xTU-C is used in someinstances. An ME 144 likewise maintains an MIB of performance datapertaining to ATU-C 142. The AN 140 may be coupled to a broadbandnetwork 170 or other network, as will be appreciated by those skilled inthe art. ATU-R 122 and ATU-C 142 are coupled together by a loop 130,which in the case of ADSL typically is a telephone twisted pair thatalso carries other communication services.

Several of the interfaces shown in FIG. 1 can be used for determiningand collecting performance data. The Q-interface 155 provides theinterface between the NMS 150 of the operator and ME 144 in AN 140. Allthe parameters specified in the G.997.1 standard apply at theQ-interface 155. The near-end parameters supported in ME 144 are derivedfrom ATU-C 142, while the far-end parameters from ATU-R 122 can bederived by either of two interfaces over the U-interface. Indicator bitsand EOC messages, which are sent using one of the embedded channels 132and are provided at the PMD layer, can be used to generate the requiredATU-R 122 parameters in ME 144. Channels 132 are part of the managementinterface of G.997.1. Alternately, the OAM (Operations, Administrationsand Management) channel and a suitable protocol can be used to retrievethe parameters from ATU-R 122 when requested by ME 144. Similarly, thefar-end parameters from ATU-C 142 can be derived by either of twointerfaces over the U-interface. Indicator bits and EOC messages, whichare provided at the PMD layer, can be used to generate the requiredATU-C 142 parameters in ME 124 of NT 120. Alternately, the OAM channeland a suitable protocol can be used to retrieve the parameters fromATU-C 142 when requested by ME 124.

At the U-interface (which is essentially loop 130), there are twomanagement interfaces, one at ATU-C 142 (the U-C interface 157) and oneat ATU-R 122 (the U-R interface 158). Interface 157 provides ATU-Cnear-end parameters for ATU-R 122 to retrieve over the U-interface 130.Similarly, interface 158 provides ATU-R near-end parameters for ATU-C142 to retrieve over the U-interface 130. The parameters that apply maybe dependent upon the transceiver standard being used (for example,G.992.1 or G.992.2).

The G.997.1 standard specifies an optional OAM communication channelacross the U-interface. If this channel is implemented, ATU-C and ATU-Rpairs may use it for transporting physical layer OAM messages. Thus, thetransceivers 122, 142 of such a system share various operational andperformance data maintained in their respective MIBs.

More information can be found regarding DSL NMSs in DSL Forum TechnicalReport TR-005, entitled “ADSL Network Element Management” from the DSLForum, dated March 1998, which is well known to those skilled in theart. Also, as noted above, DSL Forum Technical Report TR-069, entitled“CPE WAN Management Protocol” dated May 2004 is well known to thoseskilled in the art. Finally, DSL Forum Technical Report TR-064, entitled“LAN-Side DSL CPE Configuration Specification” dated May 2004 is wellknown to those skilled in the art. These documents address differentsituations for CPE side management. More information about VDSL can befound in the ITU standard G.993.1 (sometimes called “VDSL1”) and theemerging ITU standard G.993.2 (sometimes called “VDSL2”), as well asseveral DSL Forum working texts in progress, all of which are known tothose skilled in the art. Additional information is available in the DSLForum's Technical Report TR-057 (Formerly WT-068v5), entitled “VDSLNetwork Element Management” (February 2003) and Technical Report TR-065,entitled “FS-VDSL EMS to NMS Interface Functional Requirements” (March2004) and Technical Report TR-106 entitled “Data Model Template forTR-069 Enabled Devices,” as well as in the revision of ITU standardG.997.1 for VDSL2 MIB elements, or in the ATIS North American DraftDynamic Spectrum Management Report, NIPP-NAI-2006-028R4. Furtherinformation may be found in DSL Forum draft working texts WT-105entitled “Testing & Interoperability: ADSL2/ADSL2plus Functionality TestPlan” and WT-115 entitled “Testing & Interoperability: VDSL2Functionality Test Plan” and WT-121 entitled “DSL Home Technical: TR-069Implementation Guidelines.”

As will be appreciated by those skilled in the art, at least some of theoperational data and/or parameters described in these documents can beused in connection with embodiments of the present invention. Moreover,at least some of the system descriptions are likewise applicable toembodiments of the present invention. Various types of operational dataand/or information available from a DSL NMS can be found therein; othersare known to those skilled in the art.

FIG. 2 includes one or more CPE side devices 205 that may be coupled toa CPE modem or other DSL device 210 by a LAN 208. Modem 210 is coupledto a DSLAM or other upstream DSL device 215 by a twisted pair or othersuitable DSL connection 213. DSLAM 215 can be coupled to a regional orother broadband network that includes a broadband remote access server(BRAS) or the like, as will be appreciated by those skilled in the art.An auto-configuration server (ACS) 220 can be part of and/or coupled toa network such as the Internet or the like. ACS 220 is coupled to DSLAM215 through a regional broadband network. ACS 220 may have a“northbound” or upstream interface 222 to a controller 225 (for example,a DSL management entity, a DSL optimizer, a DSM Center, control software(which also may be inside ACS rather than coupled to it externally),etc.) and one or more “southbound” or downstream interfaces. In FIG. 2,southbound interfaces 231, 232 couple the ACS 220 to the CPE DSL device210 and a CPE side device 205. Other interfaces according to embodimentsof the present invention are possible, as discussed in more detailbelow.

FIG. 3 is an augmented DSL system that uses the reference model of FIG.1 as a basis. Unlike the system of FIG. 1, the augmented system of FIG.3 has DSL management tools and a DSL management entity coupled to theDSL system. As seen in FIG. 3, a DSL management entity 190 (for example,housed in a server 197 coupled to the broadband network 170) permitscommunication with various system components, such as one or more DSLdevices 122, 142; one or more MEs 124, 144 in the system; the NMS 150;and/or the DSL management tools 195. The DSL management tools 195 areavailable to various system components as well. In FIG. 3 DSL managementtools 195 are coupled to the NMS 150, ME 144 and the DSL managemententity 190.

FIG. 4 is an augmented DSL system that uses the positioning diagram fromthe TR-069 report as a basis. FIG. 4 includes one or more CPE sidedevices 405 that may be coupled to a CPE modem or other DSL device 410by a LAN 408. Modem 410 is coupled to a DSLAM or other upstream DSLdevice 415 by a twisted pair or other suitable DSL connection 4-13. ADSL Manager 440 (for example, a controller, DSL management entity, a DSLoptimizer, a DSM Center, control software, etc.) is coupled to the DSLAM415, for example through the Regional Broadband Network. The DSL Manager440 may include as its components an ACS and a Service ConfigurationManager, and may have one or more “southbound” or downstream interfaces.In FIG. 4, however, the southbound interfaces 431, 434 couple the DSLManager 440 to the CPE DSL device 410 and the DSLAM 415. Otherinterfaces according to embodiments of the present invention arepossible, as discussed in more detail below.

FIG. 5A illustrates a general schematic diagram of a DSL system, showingthe layout and operation of the system. Such a layout and any otherlayouts wherein users communicate via CPE modems with DSLAMs and thelike over actual copper plant will be referred to as a “field” systemherein (as opposed to “lab” systems in which artificial topologicalconfigurations are used). In a typical topology of a DSL plant, in whicha number of transceiver pairs are operating and/or available, part ofeach subscriber loop is collocated with the loops of other users withina multi-pair binder (or bundle). After the pedestal, very close to theCustomer Premises Equipment (CPE), the loop takes the form of a dropwire and exits the bundle. Therefore, the subscriber loop traverses twodifferent environments. Part of the loop may be located inside a binder,where the loop is sometimes shielded from external electromagneticinterference, but is subject to crosstalk. After the pedestal, the dropwire is often unaffected by crosstalk when this pair is far from otherpairs for most of the drop, but transmission can also be moresignificantly impaired by electromagnetic interference because the dropwires are unshielded. Many drops have 2 to 8 twisted-pairs within themand in situations of multiple services to a home or bonding(multiplexing and demultiplexing of a single service) of those lines,additional substantial crosstalk can occur between these lines in thedrop segment.

A generic, exemplary DSL deployment scenario is shown in FIG. 5A. Allthe subscriber loops of a total of (L+M) users 591, 592 pass through atleast one common binder. Each user is connected to a Central Office (CO)510, 520 through a dedicated line. However, each subscriber loop may bepassing through different environments and mediums. In FIG. 5A, Lcustomers or users 591 are connected to CO 510 using a combination ofoptical fiber 513 and twisted copper pairs 517, which is commonlyreferred to as Fiber to the Cabinet (FTTCab) or Fiber to the Curb.Signals from transceivers 511 in CO 510 have their signals converted byoptical line terminal 512 and optical network terminal 515 in CO 510 andoptical network unit (ONU) 518. Modems 516 in ONU 518 act astransceivers for signals between the ONU 518 and users 591.

The loops 527 of the remaining M users 592 are copper twisted pairsonly, a scenario referred to as Fiber to the Exchange (FTTEx). Wheneverpossible and economically feasible, FTTCab is preferable to FTTEx, sincethis reduces the length of the copper part of the subscriber loop, andconsequently increases the achievable rates. The existence of FTTCabloops can create problems for FTTEx loops. Moreover, FTTCab is expectedto become an increasingly popular topology in the future. This type oftopology can lead to substantial crosstalk interference and may meanthat the lines of the various users have different data carrying andperformance capabilities caused by the specific environment in whichthey operate. The topology can be such that fiber-fed “cabinet” linesand exchange lines can be mixed in the same binder.

As can be seen in FIG. 5A, the lines from CO 520 to users 592 sharebinder 522, which is not used by the lines between CO 510 and users 591.Moreover, another binder 540 is common to all the lines to/from CO 510and CO 520 and their respective users 591, 592. FIG. 5B illustrates oneor more enhancements to the system of FIG. 5A, as discussed in moredetail below.

According to one embodiment of the present invention shown in FIG. 6A, acontrol unit 600 may be part of an independent entity coupled to a DSLsystem, such as a controller 610 (for example, a DSL management entity,DSL optimizer, DSM server, DSM Center or a dynamic spectrum manager)assisting users and/or one or more system operators or providers inoptimizing their use of the system. (A DSL optimizer may also bereferred to as a dynamic spectrum manager, Dynamic Spectrum ManagementCenter, DSM Center, System Maintenance Center or SMC and include and/orhave access to DSL management tools.) In some embodiments, thecontroller 610 may be an ILEC or CLEC operating a number of DSL linesfrom a CO or other location. As seen from the dashed line 646 in FIG.6A, the controller 610 may be in the CO 146 or may be external andindependent of CO 146 and any company operating within the system.Moreover, controller 610 may be coupled to and/or controlling DSL and/orother communication lines in multiple COs.

The control unit 600 includes collecting means 620 and analyzing means640. As seen in FIG. 6A, the collecting means 620 may be coupled to NMS150, ME 144 at AN 140, the MIB 148 maintained by ME 144 and/or the DSLManagement Tools 195 (which also may be coupled to or otherwise incommunication with ME 144). Data also may be collected through thebroadband network 170 (for example, via the TCP/IP protocol or otherprotocol or means outside the normal internal data communication withina given DSL system). One or more of these connections allows the controlunit to collect operational data from the system, including customizeddata collection and collection of data parameters that are part of thepresent invention. Data may be collected once or over time. In somecases, the collecting means 620 will collect on a periodic basis, thoughit also can collect data on-demand or any other non-periodic basis (forexample, when a DSLAM or other component sends data to the controlunit), thus allowing the control unit 600 to update its information,rules, sub-rules, etc., if desired. Data collected by means 620 isprovided to the analyzing means 640 for analysis and any decisionregarding further operation of the DSL system and/or any of itscomponents.

In the exemplary system of FIG. 6A, the analyzing means 640 is coupledto a modem and/or system operating signal generating means 650 in thecontroller 610. This signal generator 650 is configured to generate andsend instruction signals to modems and/or other components of thecommunication system (for example, ADSL transceivers and/or otherequipment, components, etc. in the system). These instructions mayinclude instructions regarding acceptable data rates, transmit powerlevels, coding and latency requirements, etc. The instructions also mayinclude control parameters and time-related information concerningtimestamped parameters used in the instructions. The instructions may begenerated after the controller 610 determines the need and/ordesirability of various parameters and processes in the communicationsystem, including embodiments of the present invention. In some cases,for example, the instruction signals can assist in improving performancefor one or more customers and/or operators using the system by allowingthe controller 610 to have better and/or more control over the operationof the communication system.

Embodiments of the present invention can utilize a database, library orother collection of data pertaining to the data collected, decisionsmade regarding relevant parameters, past decisions regarding suchparameters, etc. This collection of reference data may be stored, forexample, as a library 648 in (or outside of) the controller 610 of FIG.6A and used by the analyzing means 640 and/or collecting means 620.

In some embodiments of the present invention, the control unit 600 maybe implemented in one or more computers such as PCs, workstations or thelike. The collecting means 620 and analyzing means 640 may be softwaremodules, hardware modules or a combination of both, as will beappreciated by those skilled in the art. When working with a largenumbers of modems, databases may be introduced and used to manage thevolume of data collected.

Another embodiment of the present invention is shown in FIG. 6B. A DSLoptimizer 665 operates on and/or in connection with a DSLAM 685 or otherDSL system component, either or both of which may be on the premises 695of a telecommunication company (a “telco”). The DSL optimizer 665includes a data collection and analysis module 680, which can collect,assemble, condition, manipulate and supply operational data for and tothe DSL optimizer 665 (where, as with any embodiments of the presentinvention, the operational data can include performance data as well).Module 680 can be implemented in one or more computers such as PCs orthe like. Data from module 680 is supplied to a DSM server module 670for analysis. Information also may be available from a library ordatabase 675 that may be related or unrelated to the telco. A profileselector 690 may be used to select and implement profiles such as dataand/or control parameters and/or values. Profiles and any otherinstructions may be selected under the control of the DSM server 670 orby any other suitable manner, as will be appreciated by those skilled inthe art. Profiles selected by selector 690 are implemented in the DSLAM685 and/or any other appropriate DSL system component equipment. Suchequipment may be coupled to DSL equipment such as customer premisesequipment 699. The system of FIG. 6B can operate in ways analogous tothe system of FIG. 6A, as will be appreciated by those skilled in theart, though differences are achievable while still implementingembodiments of the present invention.

Embodiments of the present invention, used in connection with DSLManagement Interfaces, can significantly improve the managementcapabilities of a DSL network and/or improve testing relating to DSLequipment and services. These benefits in turn create opportunities forDSL providers to offer equipment and services with higher performanceand at a lower total cost.

Embodiments of the present invention utilize improved methods,techniques, computer program products, apparatus, devices, etc. topermit better control and operation of a DSL system or similar digitalcommunication system, both in the case of field systems and in the caseof lab systems, as further explained and defined below. Variousembodiments include the implementation of timestamping (that permitsmore accurate measurement, monitoring, control, etc. of a system),customized data collection techniques, extended parameter definitionsfor data and/or control parameters, and implementation of these in bothfield and lab settings.

Embodiments of the present invention relate to interfaces between a DSLManagement Entity and a DSLAM, and between a DSL Management Entity and aDSL CPE modem. These are illustrated in FIG. 7A. In system 710 of FIG.7A, a DSL management entity 712 is coupled to a DSLAM (or other upstreamDSL device) 714 and to one or more CPE modems (or other downstream DSLdevices) 716. DSLAM 714 and modems 716 are coupled to each other via DSLloops 715. DSL management entity 712 communicates with DSLAM 714 usingan interface 722. DSL management entity 712 communicates with modems 716using an interface 724. Embodiments of the present invention define newand improved ways in which these interfaces 722, 724 can be used.Moreover, embodiments of the present invention can be used with a“field” or a “lab” communication system.

There are various current DSL management interfaces that are well knownto those skilled in the art, including those in the following:

ITU-T standard G.997.1, “Physical layer management for digitalsubscriber line transceivers,” and

DSL Forum TR-069, “CPE WAN Management Protocol;”

ATIS Draft Report, “Dynamic Spectrum Management,”NIPP-NAI-2005-031G.997.1 specifies the physical layer management for DSLtransmission systems based on the usage of indicator bits and EOCmessages defined in the G.992.x and G.993.x series of ITU-TRecommendations and the clear embedded operation channel defined inG.997.1. It also specifies Network Management elements content forconfiguration, fault and performance management.

G.997.1 defines the Q interface between an Access Node (referred to atsome points in the present disclosure as a DSLAM or other DSL device)and any Network Management Systems, which may be considered part of theDSL Management Entity in embodiments of the present invention. TR-069describes the CPE WAN Management Protocol, intended for communicationbetween a CPE and an Auto-Configuration Server (ACS), which may beconsidered part of the DSL Management Entity in embodiments of thepresent invention. These are shown in FIG. 7B, in which DSL ManagementEntity 742 is available to:

CPE modem 746 via interface 754; and

DSLAM 744 via interface 752. The DSLAM 744 and modem 746 are coupled toone another by DSL loop 745.

Embodiments of the present invention overcome at least some of thelimitations of the interfaces defined in G.997.1 and TR-069, such as:

No dating or time identification capability for data or controlparameters; [0075]

No customizable data collection for each DSL line;

Insufficient control parameters for DSL link configuration; and

Insufficient reported data parameters.

TR-069 defines a “CPE parameters” list in its Appendix B. Theseparameters can be accessed for reading, or (for a subset of them) forwriting using the Remote Procedure Call (RPC) methods defined inAppendix A of TR-069. Examples of embodiments of the present inventionfocus mainly on the parameters under the following “branches” of Table61 of TR-069:

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Interface Config; and

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Diagnostics. Several of theparameters under the first of the above branches are defined as holding“current” values. For example:

Upstream Attenuation

Downstream Attenuation

Upstream Power

Downstream Power

However, the definition of “current” is elusive, because multipleoperations (each with considerable processing delay) are required tocomplete the update of these parameters. In some cases, it may beimpossible for DSL equipment to update these parameters continuously.Thus, the exact length of time since the last update of these parametersis really unknown.

The parameters defined under the second of the above branches areintended to be used only after a diagnostics operation has beencompleted. However, most of these parameters can also be computedwithout a diagnostics operation. They can be derived during normalinitialization of the modem, or they can even be updated duringshowtime. But the problem of not knowing exactly when these parameterswere last computed/updated remains.

Finally, there is the problem of accessing these parameters to write tothem. With existing schemes, there is no way to schedule a writeoperation with a known and/or specified delay. This may be desirable,for example, when multiple write parameters need to be written in aspecific order.

Section 7 of G.997.1 defines Management Information Base (MIB) elements,and explains which of them can be read and written through the Qinterface. Like the situation with TR-069, there are such elements forwhich a last update time is unknown. Specifically, most of the elementsunder the “Line Test, Diagnostic and Status Parameters” group (perG.997.1 Tables 7-23 and 7-24) are such that their time of computation isunclear. Such computation may have taken place during any of thefollowing times:

Diagnostics execution

Normal initialization of modem

Normal operation of modem (showtime)

On the other hand, writing to MIB elements does not include anycapability for scheduling or otherwise identifying when a controlparameter might be enforced and/or implemented. There is no way todistinguish between performing a write operation and forcing animmediate re-initialization of a modem or other DSL device, and a writeoperation expecting the modem to adapt gracefully without exitingshowtime or otherwise interrupting normal operation. Examples ofelements requiring such a feature can be found under the “Lineconfiguration profile” and “Channel configuration profile” groups (perG.997.1 Tables 7-9 to 7-12).

Beyond the limitations of the current recommendations associated with alack of a timestamp, DSL systems may consist of multiple components, asseen in the Figures. Such components do not always share a commonreference clock. When one or more data or control parameters are passedfrom one component to another, information regarding the time of datacollection (or, for example, the time for application of a controlparameter or any other time-related action) may be lost or may have tobe translated into a different format or a different value. FIG. 5Bexemplifies this situation, wherein parameters are exchanged amongmultiple entities such as a DSL optimizer 505 (or other controller suchas a Spectrum Management Center, DSL Manager, Controller, DSM Center,etc.), a DSLAM Management entity 504, an ATU-C 503, an ATU-R 502, and aCPE Management entity 501. Each of the components of the DSL system ofFIG. 5B may have independent clocks, may be unable to share theirclocks, or may be unable to provide reliable clock information to othercomponents for example because of interface limitations. Embodiments ofthe present invention address this limitation of such systems. As aresult of such limitations, an interface with a timestamping facilityfor data and/or control parameters is needed. Furthermore, use oftimestamps allows the direct computation of various inter-eventdurations, such as the computation of a measurement window (based ondata collected on timestamps specified by the DSL optimizer) forinstance between impulse noise events. In such an example, each impulsenoise occurrence can be associated with a timestamp, which allows thederivation of such quantities such as the duration of an impulse noiseevent, the time duration between consecutive impulse noise events, andstatistics of the aforementioned durations including probabilitydistributions, averages, standard deviations, medians, minimum/maximumvalues, and others, as will be appreciated by those skilled in the art.

According to the present invention, a timestamp can be associated withthe “CPE parameters” of TR-069 or the “MIB elements” of G.997.1 with atime indication of when they were last updated (for read-onlyparameters), or of when they should be enforced (for write parameters).One example of this is shown in FIG. 8A, where a packet 810 includes atimestamp 816 that is associated with the name 812 and value 814 of theoperational parameter. For read-only (data) parameters, the timestampcould include one or more of the following types of information:

Was the update performed during a particular phase and/or in a specificoperating mode such as diagnostics, normal initialization, or showtime?

When was update performed relative to a time reference? (for example,relative to the start of the most recent re-initialization, or relativeto absolute time, which can be useful, for example, in computingmeasurement windows) For write (control) parameters, the timestamp couldinclude one or more of the following types of information:

Will the update force an initialization?

Will the update be enforced immediately, with a certain delay, or withthe next initialization?

What is the delay of the update relative to a known time reference?

The general concept can be implemented with any of multiple approaches,as will be appreciated by those skilled in the art. In one approach,illustrated in FIG. 8B, data and/or control parameters 822, 824associated with an identical timestamp 826 can be grouped together in asingle packet 820 to be transferred over a DSL Management interface. Asingle timestamp thus is associated with all the parameters.

Alternatively, time markers can be defined and used to provide thetiming information for the parameters. For example, in FIG. 8C anoperational parameter 832 is associated with a time marker 834 in apacket 830. A number of time markers can be defined as shown in thetable of FIG. 8C. Each operational parameter can then be associated withone of the pre-defined time markers. As will be appreciated by thoseskilled in the art, using time markers can be implemented as anextension of the TR-069 RPC methods using the following steps:

1. A new set of CPE parameters must be introduced to store Time Markers.

2. The ParameterValueStruct structure definition (per Table 11 inA.3.2.1 in TR-069) must be extended to include Time-Marker as one of thestructure members, thus creating the new structureParameterValueTimeStruct.

3. The GetParameterValues method (per A.3.2.2 in TR-069) must beenhanced to allow for ParameterValueTimeStruct elements in theParameterList array. Whenever GetParameterValues is called to read thevalues of time-critical CPE parameters, the Time Markers should also beincluded in the ParameterList.

4. The SetParameterValues method (per A.3.2.1 in TR-069) must beenhanced to allow for ParameterValueTimeStruct elements in theParameterList array. Whenever SetParameterValues is called to write totime-critical CPE parameters, the corresponding Time Markers should alsobe included in the ParameterList.

Therefore, according to some embodiments of the present invention, oneor more of which are shown in FIG. 10A, a method 1000 of operating a DSLlab and/or field system (and/or a computer program product implementingsuch methods) can include timestamping used in connection with one ormore operational parameters (for example, read, data, write, control,operational, etc. parameters). Generally, one or more operationalparameters are provided at 1020 and a timestamp is appended tothat/those operational parameter(s) at 1050. The operational parameterthen can be used at 1060 in operating the DSL system (for example, as adata parameter or a control parameter) or can otherwise be used toassist in operating the DSL system (which can be a field DSL system, alab DSL system such as the one shown in FIG. 9 explained in more detailbelow, etc.). As noted above, appending the timestamp can be implementedby associating the timestamp with the name and value of the operationalparameter or in other ways described herein and otherwise apparent tothose skilled in the art. The DSL devices with which the presentinvention can be used include (but are not limited to) modems, DSLAMs,line cards, remote terminals, line terminals, Component ManagementSystems, Auto-Configuration Servers, Element Management Systems and thelike. Embodiments of the present invention can be implemented in DSLsystems such as those shown and discussed herein and others known tothose skilled in the art. This description of the timestamp appliescases where all DSL system components have a common time reference.

Where a data parameter (that is, a parameter that is read-only) isinvolved, the timestamp can be a phase identification and/or a timereference. A phase identification can identify an operating mode a DSLor other system was in when the data parameter was last updated or anyother temporal description regarding phase of operation. Examples ofoperating modes include diagnostics, normal initialization, showtime,etc. A time reference can be a point in time defined by absolute time, apoint relative to one or more phase transitions (for example, frominitialization to showtime), a point in time defined relative to one ormore phase-defined events (for example, 30 seconds after enteringshowtime, 564 seconds after last initialization, etc.), etc.

Where a control parameter (that is, a parameter that is written) isinvolved, the timestamp can be, for example, information regardingwhether the update will force initialization, information regarding whenthe update will be enforced and/or implemented, information regardingany delay between a known time reference and the enforcement and/orimplementation of the update, etc. Other useful and implementabletimestamps are known to those skilled in the art. Computation ofintervals between timestamps for various quantities is also thenpossible, for example to compute measurement windows and/or the numberof events, changes or other quantities of interest during such acomputed interval, as will be appreciated by those skilled in the art.

When a number of operational parameters have or are to be assigned thesame timestamp, grouping of the operational parameters can be used, asnoted above. For example, a number of operational parameters can begrouped together and then have a single timestamp appended to the group.In other cases, a group of timestamps can be defined and identified bytime markers. Appending the timestamp to an operational parameter thencan be accomplished by associating one of the defined time markers withthe operational parameter.

In another embodiment of the present invention, one example of which isshown in FIG. 10B, a timestamp can be obtained using coordinating orsynchronizing communications between components in a DSL system.According to method 1001, a first DSL component sends a request or otherinitiating communication to a second DSL component at 1070 (this requestmay contain a timestamp containing the current time according to thefirst DSL component). The second DSL component responds at 1080 with aresponse containing a timestamp containing the current time according tothe second DSL component. The response from the second componenttypically is received after the initiating communication. Due to therelatively short period of time over which the second DSL componentsends the response to the first DSL component, the timestamp containedin the response can be used by the first DSL component to synchronizewith the second DSL component. Such a timestamp is assigned/created at1090. Any such synchronizing event can thus be used by one or morecomponents in the DSL system (such as those shown in the exemplarysystem of FIG. 5B). As will be appreciated by those skilled in the art,any other type of synchronizing event can be used to establish a pointin time to act as the basis for a timestamp. In another embodiment, thesecond DSL component may periodically transmit a message containing atimestamp to a first DSL component, without the first DSL componentsending a request to the second DSL component. Moreover, as also will beappreciated by those skilled in the art, the delay between an initiatingcommunication and a responding communication or confirmation can beimplemented so that the delay is negligible relative to the requiredaccuracy of the timestamp (for example, a delay of minutes is negligiblewhen the timestamp merely needs to be accurate as to a number of hours).

Another embodiment of this technique comprises a method wherein thefirst DSL component (for example, an ATU-C, an ATU-R, a DSLAM Managemententity, a CPE Management entity, etc.) sends a series of commands to thesecond DSL component at 1070, after which the first component receivesthe corresponding response(s) at 1080. The series of commands can be asfollows:

1. Request update of one or more parameters, for example “Update TestParameters” command using the EOC channel of the ITU-T G.993.2Recommendation (VDSL2).

2. Perform parameter read operation, for example “PMD Test ParameterRead” or “Management Counter Read” command using the EOC channel of theITU-T G.993.2 Recommendation (VDSL2).

3. Record as timestamp at 1090 for the parameters the time at which theupdate request was sent. In another embodiment of the present invention,a timestamp can be obtained when a first component of the DSL system(for example, an ATU-C, an ATU-R, a DSLAM Management entity, a CPEManagement entity, etc.) includes in its response to a second componentof the DSL system information about the time at which parameters weremeasured. For example, the “PMD Test Parameter Read” responses of VDSL2(see Table 11-26/G.993.2) may incorporate a time/date field. Such afield may apply either to a single parameter (for example, for “singleread”), or to multiple parameters (for example, “multiple read,” “nextmultiple read,” “block read,” etc.), where the field represents theexact time at which the one or more parameters were measured. Somereported quantities may be one or more accumulated values for measuredevents since the last measurement period. When both are timestamped,then the number of events per time interval can be computed as the valuedivided by the difference in timestamps. Furthermore, event durationsand time durations between consecutive events may be derived, as well asstatistics of such quantities, including distributions, averages,variances, medians, maximum and minimums. Those skilled in the art willunderstand that such adaptations are part of the present invention andare included within the scope of the claims that follow.

As will be appreciated by those skilled in the art, computer programproducts using embodiments of the present invention can include amachine readable medium and program instructions contained in themachine readable medium. The program instructions specify a method ofoperating a DSL system according to one or more of the methods describedherein.

In TR-069, the data collection for the DSL Physical Layer parameters isperformed in exactly the same way for all CPEs:

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Interface Config parametersshould hold current values (e.g. Downstream Noise Margin).

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Diagnostics parametersshould hold values from the last diagnostics session (e.g. SNRpsds).

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Interface Config Stats Totalparameters hold total statistics (e.g. FEC Errors since the beginning ofdata collection).

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Interface Config StatsShowtime parameters hold statistics accumulated since the most recentshowtime.

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Interface Config Stats LastShowtime parameters hold statistics accumulated since the second mostrecent showtime.

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Interface Config StatsCurrent Day parameters hold statistics accumulated during the currentday.

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Interface Config StatsQuarter Hour parameters hold statistics accumulated during the currentquarter hour.

There also are parameters indicating the number of seconds since thebeginning of data collection, since the most recent showtime, etc.

This approach misses the capability to adjust the data collectionindependently for each line. For example, for problematic or otherlines, it may be desirable to be able to collect data more frequentlycompared to stable lines. The additional data can be used to diagnoseproblems and suggest solutions. On the other hand, requiring all linesto collect data very frequently typically is impractical, because itleads to much higher memory and communication bandwidth needs that arenot justifiable for all lines involved.

In G.997.1, there are MIB elements for:

Line performance monitoring parameters (e.g. Errored Seconds)

Channel performance monitoring parameters (e.g. FEC corrections)

ATM data path performance monitoring parameters (e.g. HEC violations)

For these elements, counters are defined over periods of 15 minutes andof 24 hours. For Errored Seconds, Severely Errored Seconds, andUnavailable Seconds, counters are also stored for the past 16 intervalsof 15 minute duration (see 7.2.7.9).

There also are MIB elements for (1) line test, diagnostics and statusparameters (e.g. SNR margin downstream), and (2) channel test,diagnostics and status parameters (e.g. actual interleaving delay).These elements store only “current” values.

Finally, there are MIB elements storing threshold values for monitoringparameters. When the threshold values (defined over periods of 15minutes and of 24 hours) are exceeded, then a “threshold report” isgenerated and transmitted over the Q-interface.

Like TR-069, the definition of the MIB elements in G.997.1 does notallow customized data collection for each line. It therefore isimpossible to collect certain parameters at a faster rate (or to collectmore data points within a given time period), so that more informationcan be collected for problematic lines.

Embodiments of the present invention permit customized and/or adaptivedata collection to define the data collection procedure individually foreach CPE, DSLAM or other DSL device. Multiple values are stored for eachparameter, each corresponding to different instants in time. The timesat which the parameter values are stored are programmable for each DSLdevice individually. Such collected parameter values can be associatedwith a timestamp field.

An example illustrates benefits and implementation of one embodiment ofthe present invention. Assume that CPE A is a stable line, which needsonly occasional monitoring. Parameters (such as the SNR margin) then canbe collected infrequently or on a “normal” basis (for example, everyhour), simply to make sure that the line remains stable, as shown in thefollowing table:

TABLE 1 Example of Adaptive Data Collection for stable line CPE A(stable line) Value of SNR Margin at 2:00 pm Value of SNR Margin at 3:00pm Value of SNR Margin at 4:00 pm Value of SNR Margin at 5:00 pm

However, if CPE B is a problematic line, closer monitoring can be usedto determine the cause(s) of instability. Parameters such as the SNRmargin then should be collected more frequently (for example, everyquarter hour) to better pinpoint the time at which the problem arises,as shown in the following table:

TABLE 2 Example of Adaptive Data Collection for problematic line CPE B(problematic line) Value of SNR Margin at 4:00 pm Value of SNR Margin at4:15 pm Value of SNR Margin at 4:30 pm Value of SNR Margin at 4:45 pmValue of SNR Margin at 5:00 pm

Stability of a DSL loop can be determined by measuring one or moreperformance parameters and comparing such parameters to predeterminedthresholds. Such comparisons can be performed for any of current and/orhistorical data, and for downstream and/or upstream transmissions. Suchperformance parameters can include data rate, SNR margin, FEC errors,decoder errors, line/noise/SNR characteristics, latency path reporteddata, impulse noise statistics, maximum attainable data rates, retraincounts, code violations, reported DSL defects and others.

Generally, customized data collection according to the present inventionmay require that each parameter (or group of parameters) be associatedwith one or more of the following variables:

Data collection start time

Data collection period

Data collection end time, or total number of data collection points Thefirst and third variables can be omitted in some embodiments.

Customized data collection according to the present invention can beintegrated easily with TR-069 or with G.997.1, as will be appreciated bythose skilled in the art. For TR-069 the following steps can be used toaugment TR-069 operation:

New CPE parameters (or MIB elements) must be created for specifyingcustomized data collection.

CPE parameters (or MIB elements) with customized data collectioncapability must be extended to vector types. Whenever data collectionfills up a vector, either data collection must stop, or the new valuesmust overwrite the oldest values.

Finally, “threshold reporting” can enhance data collection with TR-069.A simple way to achieve this is by modifying the Set ParameterAttributes method (per A.3.2.4 in TR-069). Currently, setting theNotification field in the SetParameterAttributesStruct structure allowsthe CPE to notify the DSL Management Entity of a parameter that haschanged value. By including an additional field to theSetParameterAttributesStruct structure, the notification can betriggered by events such as a parameter exceeding a certain threshold.Alternatively, a notification may be sent when a parameter value fallsbelow a threshold value. The Trigger field may have the followingallowed values:

A special value indicating that the triggering event is any change ofthe value.

A range of threshold values for triggering a notification.

Methods for adaptive data collection in a DSL loop according to one ormore embodiments of the present invention are shown in FIGS. 11 and 12.The method 1100 of FIG. 11 begins with the selection of one or more dataparameters for customized collection at 1110, which may includeevaluating performance of the DSL loop while the DSL loop is using afirst data collection procedure, such as a normal data collectionoperation per TR-069 or G.997.1. A second data collection procedure forthe DSL loop based on the evaluation of the DSL loop performance canthen be determined (for example, collecting data more or less often, orcollecting more or fewer data points for evaluating the loop'sperformance) at 1120. Once a different data collection procedure hasbeen determined and/or defined at 1120, the attributes can be sent froma controller (for example, a DSL management entity) to a DSL device (forexample, a CPE modem) at 1130 and thereafter operation of the DSL loopcan be adapted at 1140 to use the second data collection procedure bysending the value/vector of values for each data parameter to thecontroller from the DSL device. Thus it may be the data collectionfrequency that is adjusted during performance of such methods.

Where threshold reporting is used, as shown by method 1200 in FIG. 12,the data parameter is chosen at 1210 and assigned one or more attributesat 1220. Again, the attributes are sent at 1230 from the controller tothe DSL device, after which the data parameter value(s) are sent fromthe DSL device back to the controller at 1240 when the thresholdconditions are met.

As will be appreciated by those skilled in the art, such methods can beapplied to all the loops in a DSL binder or any other suitable group sothat data collection can be appropriate on a loop-by-loop basis. Suchmethods can be performed by computer program products or a controller ofsome sort, such as a DSL optimizer, DSM Center or the like. Moreover,these methods can be extended so that one or more operational parametersmay be considered and evaluated, as appropriate. For each suchoperational parameter, a data collection start time, collection periodand end time can be designated. In some cases, as noted above, it mayonly be necessary to designate a data collection period for eachoperational parameter. The loops with which such methods are used alsocan be programmed and/or otherwise configured to notify a controller orthe like whenever an operational parameter threshold value or range isachieved or lost, such as a maximum value, a minimum value, a sufficientchange in the operational parameter value or where the operationalparameter's value falls outside or within a specified range. As notedabove, one or more of these methods can be implemented as an extensionof TR-069 and/or G.997.1, as will be appreciated by those skilled in theart.

In TR-069, the DSL Physical Layer parameters are defined under thefollowing branches:

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Interface Config.

InternetGatewayDevice.WANDevice.{i}.WAN-DSL Diagnostics. None of theseparameters can be written by a DSL Management Entity, except forInternetGatewayDevice.WANDevice.{i}. WAN-DSL Diagnostics LoopDiagnostics State, which is used to trigger DSL diagnostics.

This limitation of TR-069 implies that the only path for configuring theDSL Physical Layer of the CPE is through the means provided by G.997.1,or through the message exchange performed between a DSLAM and CPE duringinitialization. However, this solution is problematic in a variety ofcircumstances:

Broken DSLAM controls—In certain situations, it is impossible to controlthe CPE parameters from the DSL Management Entity due to implementationissues. There are several points where the communication path may bebroken. For the path to work properly, a large number of elements needto function properly—the Q-interface must include the needed controls,the DSLAM implementation of the management portion must be complete, themessage overhead path between the DSLAM and CPE must be implementedcorrectly, and the CPE implementation of the management portion must becomplete.

Restricted set of G.997.1 CPE configuration parameters—It would beadvantageous to have many of the currently CPE parameters not currentlydefined as programmable in G.997.1 be programmable. For example, itwould be helpful to be able to program interleaved path parameters suchas N, R, D, S and I.

Parameter values available too late to the CPE—Some parameters arecommunicated from the DSLAM to the CPE during various stages ofinitialization (for example, maximum SNR margin). However, the CPE mayneed to know these parameter values much earlier in order to optimizethe link. For example, in the case of maximum SNR margin, the CPE mustdecide the proper transmission PSD level at an early stage.

Some G.997.1 limitations related to the DSL configuration controls ofthe CPE have been mentioned above. Additionally, the G.997.1 MIBelements are missing a number of configuration parameters that arevaluable for DSL Management. Additional useful elements are discussedbelow.

Using embodiments of the present invention to improve the DSLconfiguration controls of the CPE, certain CPE parameters can be madeprogrammable by a controller, such as a DSL Management Entity. In someembodiments, it may be preferable that new values for such programmableCPE parameters be associated with a timestamp, as in the earlierdescriptions and as will be appreciated by those skilled in the art.

In this case, questions may arise about possible conflicts between thevalues programmed directly by the controller (DSL Management Entity) andthe values instructed by the DSLAM. There are various ways to resolvesuch conflicts:

A CPE parameter can be defined to indicate whether the DSLAM values orthe DSL Management Entity values have priority in cases of conflict.

If one or more values instructed by the DSL Management Entity results ina failed link, or in some other abnormal situation, then the CPEparameters can be reset and/or the link reinitialized with the DSLAMvalues having priority. After the link is re-established, the CPE mayreport the abnormal situation to the DSL Management Entity. A list ofcontrol parameters usable with a CPE modem for DSL configuration inconnection with the present invention is shown in Table 3, below, whichlists the parameter and comments, if any, parenthetically.

TABLE 3 Control parameters for CPE configuration Transmission SystemEnabled (Indicates which among the possible transmission systems areallowed) Power Management State Forced Power Management State EnabledL0-TIME L2-TIME L2-ATPR L2-ATPRT MAXNOMPSDdn MAXNOMPSDup MAXNOMATPdnMAXNOMATPup MAXRXPWRup PSDREF_a (Constant a for PSDREF calculation forUPBO) PSDREF_b (Constant b for PSDREF calculation for UPBO) PSDREF_klo(Electrical length for UPBO) CARMASKdn CARMASKup PSDMASKdn PSDMASKupBITCAPpsdn (Bit cap definition per subcarrier) BITCAPpsup (Bit capdefinition per subcarrier) RFIBANDSdn RFIBANDSup TARSNRMdn TARSNRMupTARSNRpsdn (Target SNR margin definition per subcarrier) TARSNRpsup(Target SNR margin definition per subcarrier) MINSNRMdn MINSNRMupMAXSNRMdn MAXSNRMup RA-MODEdn RA-MODEup RA-USNRMdn RA-USDNMup RA-UTIMEdnRA-UTIMEup RA-DSNRMdn RA-DSNRMup RA-DTIMEdn RA-DTIMEup MSGMINdn MSGMINupBITSdn BITSup GAINSdn GAINSup TSSIdn TSSIup Minimum Data Rate (Definedper bearer channel (or latency path)) Minimum Reserved Data Rate(Defined per bearer channel (or latency path)) Maximum Data Rate(Defined per bearer channel (or latency path)) Delta Data Rate (Definedper bearer channel (or latency path)) Rate Adaptation Ratio (Defined perbearer channel (or latency path)) Minimum Data Rate in Low Power Mode(Defined per bearer channel (or latency path)) Maximum InterleavingDelay (Defined per bearer channel (or latency path)) Minimum INP(Defined per bearer channel (or latency path)) Maximum BER (Defined perbearer channel (or latency path)) Data Rate Threshold Upshift (Definedper bearer channel (or latency path)) Data Rate Threshold Downshift(Defined per bearer channel (or latency path)) Interleaver path settings(Defined per latency path. May include RS codeword size, parity bytes,interleaver depth, interleaver period) Trellis transmit TU-C (Trellisencoding enabled for TU-C) Trellis receive TU-C (Trellis decodingenabled for TU-C) Trellis transmit TU-R (Trellis encoding enabled forTU-R) Trellis receive TU-R (Trellis decoding enabled for TU-R)Margin-Cap Mode_ds (or band preference) indication (Use margin-cap modeor band preference indication to choose between two loading algorithmsthat may be a function of other control parameters, for instance PSDMASKor BCAP or both, downstream) Margin-Cap Mode_us (or band preference)indication (Use margin-cap mode or band-preference indication to choosebetween two loading algorithms that may be a function of other controlparameters, for instance PSDMASK or BCAP or both, upstream) Requestmargin-cap support (ds) (Request indication of margin-cap mode support,downstream) Number of tones, cyclic prefix, cyclic suffix,transmitter/receiver window lengths, transmitter/receiver windowcoefficients, timing advance Request margin-cap support (us) (Requestindication of margin-cap mode support, upstream)

Therefore, using embodiments of the present invention, as shown in FIG.13, a method 1300 for operating a DSL system may commence with providingat 1310 at least one CPE modem device that accepts, via a TCP/IP-basedprotocol, control parameters for controlling and/or operating the DSLsystem (or at least one or more DSL devices within the DSL system, whichcan be a lab or field DSL system). The CPE modem may also be providedwith an associated timestamp. At least one operational parameter (forexample, one or more of the parameters from Table 3) can be provided at1320 as a writable control parameter for the DSL device, allowing avalue to be written at 1330 to the writable control parameter to createa written control parameter value. At 1340 the DSL device may beoperated using the written control parameter value. The DSL device mayenforce the control parameter value at a time corresponding to thepreviously provided timestamp. As with the other techniques disclosedherein, the DSL device can be any suitable device, including (but notlimited to) a CPE modem, a DSLAM, a remote terminal, a line terminal, aConfiguration Management System, an Element Management System, or anyother type of DSL modem usable in the system.

As noted above, conflicts can arise. Embodiments of the presentinvention can resolve conflicts between the written control parametervalue and a conflicting parameter value by using any suitableprioritization scheme, such as granting priority to the written controlparameter value, granting priority to the conflicting parameter value,or re-initializing a DSL loop on which the DSL device operates, wherere-initializing the DSL loop can include resetting the writable controlparameter to a default parameter value. Re-initializing the DSL loopalso can include reporting any parameter conflict to a controller. Insome instances, the default parameter value may be the conflictingparameter value.

These embodiments of the present invention can be applied to variousparameters under G.997.1 and/or TR-069. As such, these methods also canbe implemented as at least part of an interface between a DSL managemententity and the DSL device. Various computer program productsimplementing one or more of the methods according to the presentinvention can be realized by those skilled in the art.

The CPE parameters defined in TR-069 and the G.997.1 MIB elements aremissing many important data parameters that are valuable for DSLManagement. Lists of data parameters usable with a CPE modem or upstreamdevice (for example, a DSLAM) for DSL configuration in connection withthe present invention are shown in Tables 4 and 5, below (as with Table3, comments pertaining to parameters are provided parenthetically withthe parameter identification).

TABLE 4 Data parameters for DSLAM monitoring Bit swap requests upstreamBit swaps performed downstream Bit swaps performed upstream ACTPSDpsdn(Actual PSD per subcarrier) ACTPSDpsup (Actual PSD per subcarrier)Downstream Power (Received power at CPE) ECHOdn (Echo PSD) ECHOup (EchoPSD) NOISEPARdn (Noise PAR) NOISEPARup (Noise PAR) Interleaver pathsettings (Defined per latency path Includes RS codeword size, paritybytes, interleaver depth, interleaver period, other interleaverparameters) Framing settings (All parameters associated with framing)Trellis downstream (Trellis coding used for downstream) Trellis upstream(Trellis coding used for upstream) Ndn (Number of tones) Nup (Number oftones) CPdn (Cyclic prefix length) Cpup (Cyclic prefix length) CSdn(Cyclic prefix length) CSup (Cyclic prefix length) TXWINLENdn(Transmitter window length) TXWINLENup (Transmitter window length)RXWINLENdn (Receiver window length) RXWINLENup (Receiver window length)TXWINdn (Transmitter window coefficients) TXWINup (Transmitter windowcoefficients) RXWINdn (Receiver window coefficients) RXWINup (Receiverwindow coefficients) Tadn (Timing advance) Taup (Timing advance)MCsupportdn (Downstream support of Margin-cap (or band-preference) moderesponse) MCsupportup (Upstream support of Margin-cap (orband-preference) mode support)

TABLE 5 Data parameters for CPE monitoring Transmission SystemCapabilities THROUGH-C (Indicates which among the transmission systemsare supported) Transmission System Capabilities THROUGH-R (Indicateswhich among the transmission systems are supported) Chipset vendor TU-CChipset vendor TU-R Modem vendor TU-C Version number TU-C Serial numberTU-C Self-test result TU-C Self-test result TU-R Loss-Of-Signal TU-CLoss-Of-Signal TU-R Loss-Of-Frame TU-C Loss-Of-Power TU-C Loss-Of-PowerTU-R No cell delineation TU-C Loss of cell delineation TU-C FEC errorsTU-C FEC errors TU-R Errored seconds TU-C Severely errored seconds TU-CLoss of signal seconds TU-C Loss of signal seconds TU-R Unavailableseconds TU-C Unavailable seconds TU-R Failed initialization counterShort initialization counter Failed short initialization counterDelineated cell count TU-C Delineated cell count TU-R User cell countTU-C User cell count TU-R Idle cell Bit Error count TU-C Idle cell BitError count TU-R Bit swap requests downstream Bit swap requests upstreamBit swaps performed downstream Bit swaps performed upstream Powermanagement state Initialization success/failure cause Last statetransmitted downstream Last state transmitted upstream LATNdn LATNupACTPSDdn ACTPSDup ACTPSDpsdn (Actual PSD per subcarrier) ACTPSDpsup(Actual PSD per subcarrier) ACTATPdn HLINdn HLINup HLOGdn HLOGup QLNdnQLNup ECHOdn ECHOup SNRdn SNRup NOISEPARdn NOISEPARup MCsupportdn(Downstream support of Margin-cap (or band-preference) mode response)BITSdn BITSup GAINSdn GAINSup TSSdn TSSup Previous data rate (Definedper bearer channel or latency path) Actual interleaving delay (Definedper bearer channel or latency path) Interleaver path settings (Definedper latency path; includes RS codeword size, parity bytes, interleaverdepth, interleaver period, other interleaver parameters) Framingsettings (All parameters associated with framing) Trellis downstream(Trellis coding used for downstream) Trellis upstream (Trellis codingused for upstream) Ndn (Number of tones) Nup (Number of tones) CPdn(Cyclic prefix length) Cpup (Cyclic prefix length) CSdn (Cyclic prefixlength) CSup (Cyclic prefix length) TXWINLENdn (Transmitter windowlength) TXWINLENup (Transmitter window length) RXWINLENdn (Receiverwindow length) RXWINLENup (Receiver window length) TXWINdn (Transmitterwindow coefficients) TXWINup (Transmitter window coefficients) RXWINdn(Receiver window coefficients) RXWINup (Receiver window coefficients)Tadn (Timing advance) Taup (Timing advance) MCsupportup (Upstreamsupport of Margin-cap (or band-preference) mode support)

Therefore, using embodiments of the present invention, as shown in FIG.14, a method 1400 for operating a DSL system may commence with providingat 1410 at least one CPE modem or upstream DSL device (for example, aDSLAM) that accepts requests from a DSL management entity for providingdata parameters measured by the DSL system (again, which can be a lab orfield DSL system). At least one operational parameter (for example, oneor more of the parameters from Table 4 or Table 5, depending on the typeof DSL device) can be provided at 1420 as a readable data parameter forthe DSL device. A timestamp associated with the operational parameter isalso provided to indicate the time of measurement of the readable dataparameter. A value is assigned at 1430 by the DSL device to the readabledata parameter to create an assigned data parameter value. A timestampis also assigned to the readable data parameter. Thereafter at 1440 theDSL device may send a response to the DSL management entity containingthe assigned data parameter value and the assigned timestamp. As withthe other techniques disclosed herein, the DSL device can be anysuitable device, as will be appreciated by those skilled in the art,including in some cases (but not limited to) a CPE modem, a DSLAM, aremote terminal, a line terminal, a Configuration Management System, anElement Management System, or any other type of DSL modem usable in thesystem.

As described in more detail below, a control unit implementing one ormore embodiments of the present invention can be part of a controller(for example, a DSL optimizer, dynamic spectrum manager or spectrummanagement center, any one of which may be part of or comprise a DSLManagement Entity). The controller and/or control unit can be locatedanywhere. In some embodiments, the controller and/or control unit residein a DSL CO, while in other cases they may be operated by a third partylocated outside the CO. The structure, programming and other specificfeatures of a controller and/or control unit usable in connection withembodiments of the present invention will be apparent to those skilledin the art after reviewing the present disclosure.

Some of the following examples of embodiments of the present inventionwill use DSL systems as exemplary communications systems. Within theseDSL systems, certain conventions, rules, protocols, etc. may be used todescribe operation of the exemplary DSL system and the informationand/or data available from customers (also referred to as “users”)and/or equipment on the system. However, as will be appreciated by thoseskilled in the art, embodiments of the present invention may be appliedto various communications systems, and the invention is not limited toany particular system. The present invention can be used in any datatransmission system for which service quality may be related to controlparameters.

Various network-management elements are used for management of DSLphysical-layer resources, where elements refer to parameters orfunctions within an DSL modem pair, either collectively or at anindividual end. A network-management framework consists of one or moremanaged nodes, each containing an agent. The managed node could be arouter, bridge, switch, DSL modem or other. At least one NMS (NetworkManagement System), which is often called the manager, monitors andcontrols managed nodes and is usually based on a common PC or othercomputer. A network management protocol is used by the manager andagents to exchange management information and data. The unit ofmanagement information is an object. A collection of related objects isdefined as a Management Information Base (MIB).

Embodiments of the present invention may be used with “field” DSLsystems as described above. Moreover, embodiments of the presentinvention may be used with “lab” systems. FIG. 9 illustrates one suchlab configuration 910. Automated testing equipment 912 is coupled to aloop/noise lab simulator 914. Such lab simulators are well known in theart and various capabilities can be used for replicating actual DSLloops or groups of loops, such as DSL binders and the like. Labsimulators are hardware and/or software equipment that simulate thebehavior of the transmission environment. Testing equipment 912 can behardware and/or software that controls the other modules of lab system910 and can collect measured data from these other devices. Device 912also is coupled to a CPE modem 916 and a DSLAM 918, as shown in FIG. 9.Each of these devices 916, 918 is coupled to the loop/noise labsimulator to recreate a given DSL loop. Finally, a packet traffic tester920 is coupled to devices 912, 916, 918 to allow tester 920 to collectdata from these various devices. Tester 920 is hardware and/or softwarethat generates and tests packet traffic. This can be done for bothupstream (CPE to DSLAM) traffic and downstream (DSLAM to CPE) traffic.

The configuration 910 can include appropriate connections among modules,as will be appreciated by those skilled in the art. For example, theconnections between the DSLAM 918 and lab simulator 914 and between theCPE modem 916 and lab simulator 914 can be short cable connections. Theconnections between the DSLAM 918 and packet traffic tester 920 andbetween the CPE modem 916 and packet traffic tester 920 can be standardinterfaces and connection means. The connection between the DSLAM 918and automated testing device 912 can use interfaces, operationalparameters, etc. defined by embodiments of the present invention and/orG.997.1. Likewise, the connection between the CPE modem 916 andautomated testing device 912 can use interfaces, operational parameters,etc. defined by embodiments of the present invention and/or TR-069.Finally, the connections between the lab simulator 914 and automatedtesting device 912 and between the packet traffic tester 920 andautomated testing device 912 can be standard interfaces and connectionmeans.

Embodiments of the present invention can be used to automate testing ofDSLAM and CPE equipment. Such techniques can make use of the interfacesdefined by aspects of the present invention discussed herein, TR-069and/or G.997.1. As explained below, use of the present invention isparticularly advantageous in such testing in a lab system setting. Oneconfiguration for automated testing of DSL equipment is shown in FIG. 9.

Many DSL equipment tests can be defined by the following steps:

(a) Configure the lab simulator;

(b) Configure the DSLAM and CPE modem(s);

(c) Configure the packet traffic tester (necessary in some tests only);and

(d) Collect data from the DSLAM and the CPE modem(s). Steps (b) and (d)may be repeated during the same test. Other variations on these methodswill be apparent to those skilled in the art.

The configuration of FIG. 9 can be used to automate the process oftesting DSL equipment. The automated test device 912 is used to controland coordinate the steps taken during each test. As will be appreciatedby those skilled in the art, various tests can be performed to evaluateequipment and techniques that might arise in a “field” system settingand to verify the capabilities of different types of equipment.

Specifically, for each test, the automated test device performs thefollowing:

Sends commands to the lab simulator to specify the loop and noiseconditions;

Uses control parameters of the present invention, G.997.1 and/or TR-069to configure the DSLAM and CPE modem(s) as specified in the testdefinition;

Sends commands to the packet traffic tester to commence trafficgeneration and testing;

Uses the data parameters of the present invention, G.997.1 and/or TR-069to collect measurements from the DSLAM and CPE modem(s).

After conclusion of the test, the collected measurements can be comparedagainst expected values to produce a pass or fail result. In othercases, the collected measurements can be used for other purposes, aswill be appreciated by those skilled in the art.

Embodiments of the present invention possess a number of advantages ascompared with other methods for verification testing. Significantbenefits can be realized in the approach described above through the useof the interfaces and/or operational parameters of the presentinvention, G.997.1 and/or TR-069 for:

Configuring the control parameters of the DSLAM and CPE; and

Collecting data parameters from the DSLAM and CPE. The use of thepresent invention for the above purposes is particularly advantageousfor various reasons, some of which are outlined below.

Advantage 1—Single interface—An alternative approach for accessing thecontrol and data parameters of the DSLAM and CPE modem(s) is to useproprietary interfaces of the corresponding DSLAM and CPE modem(s). Thisis less attractive than using the known interfaces of the presentinvention, G.997.1 and/or TR-069, since these known interfaces avoid theissues of supporting multiple proprietary interfaces.

Advantage 2—Timestamp capability—Among the standardized interfaces,neither G.997.1 nor TR-069 has a timestamp capability described above(for example, to specify the time of data collection, or the time ofapplication of control parameters). The present invention overcomes thisobstacle, which significantly facilitates verification testing.

Advantage 3—Customized data collection capability—Compared to G.997.1and TR-069, the present invention has available the extra capability ofcustomized data collection, which means that data collection can betailored to fit the needs of each verification test. Data parameters canbe collected at just the right frequency, thus avoiding collecting toomuch data on one hand, or collecting data too infrequently on the otherhand.

Advantage 4—Extended sets of data and control parameters—Compared toG.997.1 and TR-069, the present invention has many additional controland data parameters. This boosts the capabilities of the automated testdevice to configure the DSLAM and CPE modem(s) for verification testing.It also enhances the set of measurements that can be obtained from theDSLAM and CPE modem(s), thus making possible the automation of many moreverification tests.

Other embodiments of the present invention include a modem or other DSLdevice (for example, a DSLAM) using a bit and energy table loadingsub-method (for example, an algorithm or other similar process) selectedfrom a group of available sub-methods based on some observed behavior orother operational data that is obtained by the DSL device, either via anexplicit command or via information about the environment (for example,including all other control parameters). The DSL device chooses its bitloading sub-method for initialization, which can include attempting tocomply with maximum SNR margin constraints imposed and/or desired in thesystem in which the DSL device operates (a DSL loop, DSL system, DSLnetwork, which may or may not include a DSL manager of some sort). Insome cases, one of the available bit loading sub-methods might be a bitloading sub-method required, suggested, recommended, etc. by a DSL orother communications standard.

As is well known to those skilled in the art, DSL systems are requiredto maintain a probability of bit error smaller than a certain thresholdvalue (termed a bit error rate, or BER, typically 10.sup.-7). DSLsystems based on discrete multi-tone (DMT) technology (for exampleADSL1, ADSL2/2+, VDSL1 and VDSL2) transmit information over a largenumber of tones (also referred to as sub-carriers). As discussed in moredetail below, one signal-to-noise (SNR) margin can be calculated for anentire DSL system and another SNR margin calculated for a single DSLtone.

The SNR margin of a DSL system is the maximum factor by which noise canbe increased over all tones and still maintain a probability of biterror smaller than the threshold value for the information bitstransmitted over all tones. The SNR margin can be practicallyapproximated as the minimum over all tones of the per-tone SNR margin(also known as worst-case SNR margin). In some cases, the noise can bereplaced in the margin definition by another value, for example aminimum-mean-square distortion or error signal that includes effects ofimperfect modem implementation.

The SNR margin of a single DSL system tone is the maximum factor bywhich noise can be increased on the single tone and still maintain theBER for the information bits transmitted on that tone. The SNR margin ofa tone depends on the transmitted signal power on the tone, theattenuation experienced by the signal on the tone, the receiver's noisepower on the tone, the coding gain achieved by use of any codingschemes, and the constellation size on the tone (or equivalently thenumber of bits on the tone). If all else remains equal, increasing thetransmitted signal power raises the SNR margin. If all else remainsequal, increasing the number of bits lowers the SNR margin.

The transmitted signal power of a tone depends on scaling operationsperformed on the transmitter. The transmitted signal power is affectedby per tone operations for fine gain scaling (for example, gi factorsaccording to some standards), transmit spectrum shaping (for example,tssi factors according to some standards) and other tone-dependentscaling operations such as “coarse” gain scaling (for example initial orreference flat PSD levels used in initialization in some standards). Thetransmitted signal power level with no fine gain scaling (gi=1), with notransmit spectrum shaping (tssi=1), and with no other tone-dependentscaling, typically is referred to as the nominal transmitted signalpower level. DSL transmitters typically employ various scalingoperations in the digital and analog transmission path that can affectthe nominal transmitted signal power level.

The transmitted signal power of a tone (for example, using an energytable showing energy per tone) and the number of bits on a tone areconfigurable by the DSL system and are set by a DSL device such as amodem, DSLAM, etc. using a bit loading sub-method, algorithm, etc. Thesequantities are configured for the first time during initialization (alsoknown as training) of the DSL system. These quantities can be updatedduring the time of normal operation of the DSL system (also known asSHOWTIME).

The transmitted signal power of a tone and the number of bits on a toneare typically selected to meet certain constraints. Typical constraintsinclude the requirement that the data rate must be equal to or largerthan a minimum data rate, and that the data rate cannot exceed a maximumdata rate. Additional constraints can include the requirement that thetransmitted signal power on a tone must not exceed a PSD mask, and thatthe aggregate transmitted signal power over all tones not exceed amaximum aggregate transmitted signal power over all tones.

Within these constraints, the DSL system selects the transmitted signalpower of a tone and the number of bits on a tone based on servicepriorities, which are the set of criteria that are optimized or improvedin configuring these two parameters. One example of serviceprioritization is:

Maximize data rate; and

Minimize worst-case SNR margin with respect to a maximum SNR margin. Asecond service prioritization example is:

Maximize data rate; and

Minimize per tone SNR margin for each used tone with respect to amaximum SNR margin. These two service priorities differ in the way theydeal with SNR margin per tone. The second service priority specifiesthat the transmitted signal power and number of bits should be selectedfor each tone so that the resulting SNR margin for that tone remainssmaller than a maximum SNR margin or, in cases where constraints of theimplementation or applicable standard may not facilitate strictcompliance with the maximum SNR margin for a tone, then the modem wouldelect to minimize the excess with respect to this maximum SNR margin. Inother words, when this objective is met, excessively large values forSNR margin are avoided, where the definition of excessiveness relies onthe configured value of maximum SNR margin. A DMT based DSL system thatimplements this second service priority scheme can be referred to as asystem that supports margin cap mode.

Thus, according to embodiments of the present invention, a DSL devicemay have multiple bit loading sub-methods from which to choose inimplementing multiple service priorities and/or in other situations. Thepresent invention provides methods, apparatus, etc. that enable a DSLdevice to select which bit loading sub-method will be used, depending ondirect instructions/controls and/or suggestions/inferences provided tothe DSL device by the system in which the device operates, which can, insome embodiments, include a DSL manager of some kind One or more of theavailable bit loading sub-methods can be required by an applicable DSLor other communications standard, while one or more other bit loadingsub-methods available to the DSL device can be a bit loading sub-methodprogrammed into the DSL device by the device manufacturer and/orprogrammed into a chipset incorporated into the DSL device. Other typesof and sources for bit loading sub-methods will be known and apparent tothose skilled in the art. The DSL device can obtain the informationneeded to make a decision about a bit loading sub-method by reading aninterface in the DSL system in which the DSL device operates.

Complying with the objective to minimize per-tone SNR margin for eachused tone, with respect to a maximum SNR margin, yields very importantbenefits. It is well known to those skilled in the art that DSL systemswith excessive SNR margin on some or all tones do not providesubstantially more reliable communication compared to DSL systems thatavoid such excessive SNR margin. In other words, excessive SNR marginprovides no substantial incremental benefit for protecting a DSL systemagainst DSL impairment sources, for example impulse noise, abrupt noisevariance changes, etc. Thus, excessive SNR margin use in a DSL systemhas only the negative effects of increasing that DSL system's powerconsumption, and increasing the crosstalk inflicted on other DSL systemscaused by the higher transmitted signal power.

Consequently, substantial benefits can be realized in DSL systems usingembodiments of the present invention, wherein the transmitted signalpower on a tone and/or the number of bits on a tone can be selected tomeet the requirement of minimizing per tone SNR margin for each usedtone with respect to a maximum SNR margin. DSL systems employing suchmethods, or DSL systems incorporating such systems can greatly benefitfrom reducing their power consumption, and from mitigating the crosstalkthat they induce on other DSL systems.

Embodiments of the present invention can be implemented in one or moreDSL devices, such as transceiver components of a DSL system (forexample, one or more of the transceivers in the systems shown in FIGS.1-7B), including (but not limited to) a DSLAM, a CPE, a ResidentialGateway (RG), a modem, a DSL Central Office chipset, a DSL CustomerPremises chipset, an xTU-R, an xTU-C, an ATU-R, an ATU-C, a VTU-O, aVTU-R, an Access Node, a Network Terminal, a Network Element, a RemoteTerminal, etc. Any one of these devices, and any similar transceivertype of device, may be referred to as a DSL device herein.

The requirement of preserving the SNR margin of a tone to values smallerthan a maximum SNR margin for all tones presents several challenges inDSL systems. A first set of challenges relates to constraints in theselection of the transmitted signal power of a tone and the number ofbits of used in connection with that tone. The number of bits carried bya tone typically is limited as follows:

the number of bits must typically be an integer;

there may be a bits per tone maximum value (typically bi_max=15) thatmay be frequency-dependent in some advanced implementations, such asthose disclosed in U.S. Ser. No. 10/893,826, filed 19 Jul. 2004, whichis incorporated herein by reference in its entirety for all purposes,and International Application Serial No. PCT/US2006/026796, filed 8 Jul.2006, which is incorporated herein by reference in its entirety for allpurposes; and

when the number of bits is non-zero, there may be a minimum allowedvalue (bi_min=2 in ADSL1 or bi_min=1 in other DSL standards). Thetransmitted signal power per tone can be controlled by:

the nominal transmitted signal power level;

fine gains (gi); and/or

transmit spectrum shaping (tssi). Each of these quantities has a minimumallowed value, a maximum allowed value, and one or more intermediatevalues based on a step size. Additionally gi and tssi can have the valuezero. For example, in ADSL1, gi has a range between 0.1888 and 1.33, isrepresented by 12 bits, and is also allowed to have the special value of0.

During DSL system initialization, the transmitted signal power per toneand the number of bits of a tone are selected and any applicableconstraints must be met. Techniques for meeting the additionalrequirement of preserving an SNR margin per tone below a maximum SNRmargin during initialization are described below.

After initialization, the DSL receiver's noise power on one or moretones may change. This can happen because of time-variation of noise,caused by for example a new source of noise, a crosstalk or interferencesource being turned off, or a temperature change in the DSL receiver'sanalog front end. After such a noise change, the SNR margin on one ormore tones may correspondingly change. Consequently, the maximum SNRmargin requirement might not hold for certain tones and the SNR marginthen must be restored to a compliant level. Techniques for restoringsuch compliance also are described below.

As explained above, complying with a maximum SNR margin limit (sometimesreferred to as MAXSNRM) also requires that the transmitted signal powerstay within its allowed range, especially for those tones where thenumber of bits is positive. As an example, in ADSL1, the transmittedsignal power on a tone with bi>0 can range as imposed by the range ofthe fine gains (−14.5 dB to 2.5 dB), which for a nominal PSD level of−40 dBm/Hz translates into −54.5 dBm/Hz to −37.5 dBm/Hz. For suchearlier systems and techniques, such a range may prove inadequate foreliminating excess SNR margin based on techniques for transmitted signalpower reduction.

Using embodiments of the present invention, however, a DSL device canselect which bit loading sub-method it will use by using one or more ofthe embodiments shown in FIG. 15. Initialization of the DSL devicebegins at 1510 and operational data is obtained at 1520, for examplefrom an interface in the overall DSL system in which the DSL deviceoperates. This operational data might include an explicit controlsignal, command, instruction, etc. that controls which bit loadingsub-method the DSL device uses. On the other hand, the obtainedoperational data might instead provide a suggestion and/or inference tothe DSL device, suggesting which bit loading sub-method to use. Finally,the operational data might be a parameter vector or the like thatcontains information which is processed by the DSL device to make itsselection. The operational data, in some embodiments, might be providedby a DSL manager. At 1530 the bit loading sub-method is selected by theDSL device, based on the operational data previously obtained. The bitloading and energy table determination is performed at 1540, along withany other initialization steps and the DSL device begins operating at1550 using the selected bit loading sub-method. It is possible in someembodiments of the present invention that the DSL device mightupdate/change its bit loading sub-method during SHOWTIME operation at1560, though this in many cases can cause the DSL line on which the DSLdevice is operating to fail. Method(s) 1500 can be used each time theDSL device initializes, if desired.

When using a bit loading sub-method that has maximum SNR margincompliance as one of its goals, a DSL system can attempt to comply withthe per tone maximum SNR margin requirement during initialization byfollowing one or more methods shown in FIG. 16A:

1. At 1610, determining the initial configuration for transmitted signalpower and number of bits per tone (can be performed using one or moretechniques well known to those skilled in the art), the output of suchdetermination including parameters such as bi, gi, tssi, NOMPSD, PCB,etc.

2. At 1620, estimating SNR margin (MARGIN[i]) on every used tone i (theestimation, which can be performed using tables, of the SNR margin on aused tone i is based on at least one of the following: transmittedsignal power on the tone, attenuation experienced by the signal on thetone, received signal power on the tone, the receiver's noise power onthe tone or the minimum mean-square distortion or error on that tone,coding gain achieved by use of any coding schemes, and/or the number ofbits on the tone).

3. At 1630, find tones violating MAXSNRM by comparing MARGIN[i] on everyused tone i to MAXSNRM. If no tone exceeds MAXSNRM, then the procedureconcludes; the initialized DSL system complies with MAXSNRM on alltones. If one or more tones exceed MAXSNRM, then the identified tonescan, for example, constitute a set K.

4. At 1640, modifying the transmitted signal power level and/or thenumber of bits. As an example, a tone j is selected from the set K, andat least one of the following actions might then be performed:

a. Reduce transmitted signal power on tone j using available scaling.(For example, reduce gi, if the scaling factor to be reduced is notalready at its minimum allowed value. For gi in ADSL1, this minimumpossible value would be −14.5 dB.) Reducing transmitted signal powerreduces the SNR margin. An initial power-back-off of the transmitterpower or power spectral density mask may also be requested duringinitialization to establish the SNR margin at desired values.

b. Increasing the number of bits (if not already at a maximum) on tone jby at least one reduces the SNR margin. Increasing the number of bits ontone j must be matched by a corresponding decrease of the number of bitson one or more tones other than the tones in set K. In one embodiment, atone for which the number of bits is decreased (denoted as a member ofset L) can be chosen as follows:

i. If it is estimated that MARGIN[i] would still remain below MAXSNRMafter decreasing the number of bits on a tone, then the tone is assignedto set L.

ii. If no tones can be found satisfying (i), above, then one or moretone are chosen for which the number of bits is decreased to 0. Suchtones then become unused, and a MAXSNRM requirement no longer appliesfor them.

c. In some cases, the MARGIN[i] might fail to be below MAXSNRM on any orall tones. In this case, the number of bits and power level on each ofthe tones can be adjusted to mitigate MAXSNRM violation

A DSL system may comply with MAXSNRM during showtime when the noiseenvironment changes by following one or more methods according toembodiments of the present invention, for example one or more shown inFIG. 16B:

1. At 1660, estimating SNR margin (MARGIN[i]) on every used tone i (theestimation, which can be performed using tables, of the SNR margin on aused tone i is based on at least one of the following: the transmittedsignal power on the tone, the attenuation experienced by the signal onthe tone, the received signal power on the tone, the receiver's noisepower on the tone, the coding gain achieved by use of any codingschemes, and the number of bits on the tone. This estimation can bedynamically updated during SHOWTIME by any one of many techniques wellknown to those skilled in the art.

2. At 1670, find tones violating MAXSNRM by comparing determined (forexample, measured and/or estimated) MARGIN[i] on every used tone i toMAXSNRM. If no tone exceeds MAXSNRM, then the procedure goes back to 1,above; the operating DSL system complies with MAXSNRM on all tones atpresent. If one or more tones exceed MAXSNRM, then the identified tonescan, for example, constitute a set K.

3. At 1680, reconfiguring the DSL system (for example, the transmittedsignal power and/or bits/tone). As an example, a tone j is selected fromthe set K, and at least one of the following actions might then beperformed: [0233]

a. Reduce transmitted signal power on tone j using available scaling.(For example, reduce gi, if the scaling factor to be reduced is notalready at its minimum allowed value. For gi in ADSL1, this minimumpossible value would be −14.5 dB.) Reducing transmitted signal powerreduces the SNR margin. If the SNR margin requirements cannot be met,the modem may also elect to use lower initial power levels (ifavailable) during any subsequent re-initialization. The nominal mode ofoperation is that indications to use margin-cap mode are inferred orexplicitly conveyed during the first phase of training and thenapplicable for all subsequent activity including showtime. Continued usewould be inferred or conveyed at the beginning of the next retrain.

b. Increasing the number of bits (if not already at a maximum) on tone jby at least one reduces the SNR margin. In a known reconfiguration modecalled bit-swapping, the increase of the number of bits on tone j mustbe matched by a corresponding decrease of the number of bits on tonesother than the tones in set K. For some types of reconfiguration (forexample, seamless rate adaptation), the increase of the number of bitsfor tone j does not need to be matched by a corresponding decrease onother tones. In one embodiment, a tone for which the number of bits isdecreased (denoted as a member of set L) can be chosen as follows: [

i. If it is estimated that MARGIN[i] would still remain below MAXSNRMafter decreasing the number of bits on a tone, then the tone is assignedto set L.

ii. If no tones can be found satisfying (i), above, then one or moretone are chosen for which the number of bits is decreased to 0. Suchtones then become unused, and a MAXSNRM requirement no longer appliesfor them.

In connection with embodiments of the present invention, it typically isadvantageous for a DSL system on which the DSL device is operating to beable to indicate to a manager (for example, a management system, one ormore other components or elements in a DSL network, a human operator,etc., which can include one of the entities depicted in FIG. 6A or FIG.6B) that the subject DSL system is capable of complying with a MAXSNRMrequirement for every used tone. Such indication can inform a managerthat this requirement is met during initialization, during SHOWTIME, orduring both. A manager or other element of a DSL Network having such anindication may then apply spectrum management techniques appropriate forthe supplied indication to the DSL system.

An indication can assume a number of forms, as will be appreciated bythose skilled in the art. An indication can consist of a single bitreporting MAXSNRM compliance, such as the bit referenced in U.S. Ser.No. 10/893,826, filed 19 Jul. 2004, which is incorporated herein byreference in its entirety for all purposes, and InternationalApplication Serial No. PCT/US2006/026796, filed 8 Jul. 2006, which isincorporated herein by reference in its entirety for all purposes.Alternatively, the indication may consist of a bit-field reporting theservice priority followed by the DSL system, wherein the servicepriority includes the maximum SNR margin requirement. In otherembodiments of the present invention, such an indication can be denotedas “band preference” or “margin cap mode” compliance. Finally, anindirect indication of compliance with the MAXSNRM requirement can beprovided through DSL system identification. In cases where the DSLsystem correctly reports “inventory” information such as system vendor,chipset vendor, g.hs vendor, firmware version, software version,hardware version, serial number, etc., a manager or other DSL networkcomponent can use a look-up table to match the DSL system to anassembled list of DSL systems that are known to comply with therequirement. This “inventory information” and other similar informationpertaining to equipment used in a given DSL system also might be foundand/or determined in other ways and may be used as “equipmentinformation” in connection with embodiments of the present invention.

In connection with embodiments of the present invention, it alsotypically is advantageous for a DSL system to provide and/or haveavailable a corresponding control for enabling the capability to complywith a MAXSNRM requirement for every used tone. Such a control can beused by a manager to enable this requirement selectively on certain DSLmodems, for example modems and/or other DSL devices utilizing one ormore embodiments of the present invention in selecting a bit loadingsub-method to implement. A manager can enable this requirement, whichcan be implemented when a DSL device obtains operational data accordingto embodiments of the present invention, only for those DSL modemsand/or other devices where reduction of excess SNR margin and thecorresponding reduction of consumed power and induced crosstalk isvaluable. For example, if enabling this capability results in undesireddata rate reductions for some modems, then the manager might choose tohave it disabled by suggesting to or expressly instructing a DSL deviceto select a different bit loading sub-method.

There are a number of ways for DSL equipment to implement MAXSNRM,irrespective of the presence or absence of a manager and/or the presenceor absence of a mechanism to communicate with the manager. This meansthat a DSL device implementing an embodiment of the present inventioncan obtain a suggestion, inference, etc. from the operational dataobtained by the DSL device through a mechanism other than directcommunication with a DSL manager on the device's DSL system. Suchmechanisms for communication are the subject of the ATIS DSM TechnicalReport and the G.994.x ITU Handshake, G.HS standards as well as theG.997.1 Physical Layer Operations and Maintenance, G.PLOAM standard andthe various national and international ADSL and VDSL standards, theinformation of which is well known to those skilled in the art. If amanager is present, it can use one or more technique for determiningand/or estimating whether margin cap mode and/or band preference isimplemented. Three of these techniques permit at least an inferredanswer to the question “Does the DSL system support margin cap mode?” asfollows:

1—An interface between the manager and one or more DSL systems querieswith respect to support and receives one of 3 responses or no responseas follows: (1) Yes, I support margin cap mode and it is on, (2) Yes, Isupport margin cap mode and it is off, (3) No, I do not support margincap mode, or (4) “no response” (which might be interpreted by themanager as, “No, I do not support margin cap node.”).

2—Defaults are known for certain types of equipment, as suggested above,and equipment supporting margin cap mode always defaults to havingmargin cap mode turned on; those not supporting margin cap mode arepresumed to default to not having margin cap mode turned on.

3—The manager observes the reaction to various other profile commands tothe modem (for example, as disclosed in U.S. Ser. No. 10/817,128, filed2 Apr. 2004, which is incorporated herein by reference in its entiretyfor all purposes) and infers (during and/or after the observationinterval) whether or not the DSL appears to be implementing margin capmode. This no-interface implementation would observe modems that wouldchoose to implement or not implement margin cap mode (dynamically orstatic to a product) and presume the indication would be inferred otherbehavior reported from the line to the manager. Such a DSL modemimplementation that alters or chooses enabling margin cap mode so that amanager can observe and thus react is a significant improvement toearlier systems in which MAXSNRM was largely ignored, implementedarbitrarily and did not conform to imposition of MAXSNRM over all usedtones. Embodiments of the present invention thus allow implementation ofmargin cap mode with no express interface between a DSL line and themanager. This inquiry may be made separately for downstream and upstreamtransmission.

When a DSL system is known to support margin cap mode, the manager alsocould then provide a command or control indication to the DSL line to“turn on” or “turn off” (in which case the manager can presume that themodem returns to an observable state that might be presumed to be thatthe MAXSNRM only applies to the worst tone or tones of use by the DSL).This indication interface has been referred to as “band preference” butmay be known by other names like “margin cap mode.”

Generally, embodiments of the present invention employ various processesinvolving data stored in or transferred through one or more computersystems, which may be a single computer, multiple computers and/or acombination of computers (any and all of which may be referred tointerchangeably herein as a “computer” and/or a “computer system”).Embodiments of the present invention also relate to a hardware device orother apparatus for performing these operations. This apparatus may bespecially constructed for the required purposes, or it may be ageneral-purpose computer and/or computer system selectively activated orreconfigured by a computer program and/or data structure stored in acomputer. The processes presented herein are not inherently related toany particular computer or other apparatus. In particular, variousgeneral-purpose machines may be used with programs written in accordancewith the teachings herein, or it may be more convenient to construct amore specialized apparatus to perform the required method steps. Aparticular structure for a variety of these machines will be apparent tothose of ordinary skill in the art based on the description given below.

Embodiments of the present invention as described above employ variousprocess steps involving data stored in computer systems. These steps arethose requiring physical manipulation of physical quantities. Usually,though not necessarily, these quantities take the form of electrical ormagnetic signals capable of being stored, transferred, combined,compared and otherwise manipulated. It is sometimes convenient,principally for reasons of common usage, to refer to these signals asbits, bitstreams, data signals, control signals, values, elements,variables, characters, data structures or the like. It should beremembered, however, that all of these and similar terms are to beassociated with the appropriate physical quantities and are merelyconvenient labels applied to these quantities.

Further, the manipulations performed are often referred to in terms suchas identifying, fitting or comparing. In any of the operations describedherein that form part of the present invention these operations aremachine operations. Useful machines for performing the operations ofembodiments of the present invention include general purpose digitalcomputers or other similar devices. In all cases, there should be bornein mind the distinction between the method of operations in operating acomputer and the method of computation itself. Embodiments of thepresent invention relate to method steps for operating a computer inprocessing electrical or other physical signals to generate otherdesired physical signals.

Embodiments of the present invention also relate to an apparatus forperforming these operations. This apparatus may be specially constructedfor the required purposes, or it may be a general purpose computerselectively activated or reconfigured by a computer program stored inthe computer. The processes presented herein are not inherently relatedto any particular computer or other apparatus. In particular, variousgeneral purpose machines may be used with programs written in accordancewith the teachings herein, or it may be more convenient to construct amore specialized apparatus to perform the required method steps. Therequired structure for a variety of these machines will appear from thedescription given above.

In addition, embodiments of the present invention further relate tocomputer readable media that include program instructions for performingvarious computer-implemented operations. The media and programinstructions may be those specially designed and constructed for thepurposes of the present invention, or they may be of the kind well knownand available to those having skill in the computer software arts.Examples of computer-readable media include, but are not limited to,magnetic media such as hard disks, floppy disks, and magnetic tape;optical media such as CD-ROM disks; magneto-optical media such asoptical disks; and hardware devices that are specially configured tostore and perform program instructions, such as read-only memory devices(ROM) and random access memory (RAM). Examples of program instructionsinclude both machine code, such as produced by a compiler, and filescontaining higher level code that may be executed by the computer usingan interpreter.

FIG. 17 illustrates a typical computer system that can be used by a userand/or controller in accordance with one or more embodiments of thepresent invention. The computer system 1700 includes any number ofprocessors 1702 (also referred to as central processing units, or CPUs)that are coupled to storage devices including primary storage 1706(typically a random access memory, or RAM), primary storage 1704(typically a read only memory, or ROM). As is well known in the art,primary storage 1704 acts to transfer data and instructionsuni-directionally to the CPU and primary storage 1706 is used typicallyto transfer data and instructions in a bi-directional manner. Both ofthese primary storage devices may include any suitable of thecomputer-readable media described above. A mass storage device 1708 alsois coupled bi-directionally to CPU 1702 and provides additional datastorage capacity and may include any of the computer-readable mediadescribed above. The mass storage device 1708 may be used to storeprograms, data and the like and is typically a secondary storage mediumsuch as a hard disk that is slower than primary storage. It will beappreciated that the information retained within the mass storage device1708, may, in appropriate cases, be incorporated in standard fashion aspart of primary storage 1706 as virtual memory. A specific mass storagedevice such as a CD-ROM may also pass data uni-directionally to the CPU.

CPU 1702 also is coupled to an interface 1710 that includes one or moreinput/output devices such as such as video monitors, track balls, mice,keyboards, microphones, touch-sensitive displays, transducer cardreaders, magnetic or paper tape readers, tablets, styluses, voice orhandwriting recognizers, or other well-known input devices such as, ofcourse, other computers. Finally, CPU 1702 optionally may be coupled toa computer or telecommunications network using a network connection asshown generally at 1712. With such a network connection, it iscontemplated that the CPU might receive information from the network, ormight output information to the network in the course of performing theabove-described method steps. The above-described devices and materialswill be familiar to those of skill in the computer hardware and softwarearts. The hardware elements described above may define multiple softwaremodules for performing the operations of this invention. For example,instructions for running a controller may be stored on a mass storagedevice and executed on CPU 1702 in conjunction with primary memory 1706.In one embodiment of the present invention, the controller is dividedinto software submodules.

The many features and advantages of the present invention are apparentfrom the written description, and thus, the appended claims are intendedto cover all such features and advantages of the invention. Further,since numerous modifications and changes will readily occur to thoseskilled in the art, the present invention is not limited to the exactconstruction and operation as illustrated and described. Therefore, thedescribed embodiments should be taken as illustrative and notrestrictive, and the invention should not be limited to the detailsgiven herein but should be defined by the following claims and theirfull scope of equivalents, whether foreseeable or unforeseeable now orin the future.

What is claimed is:
 1. A method of operating a DSL system, the method comprising: providing an operational parameter; appending a timestamp to the operational parameter; and using the operational parameter in operating the DSL system.
 2. The method of claim 1 wherein the operational parameter is a data parameter.
 3. The method of claim 2 wherein the timestamp comprises at least one of the following: a phase identification; or a time reference.
 4. The method of claim 3 wherein the phase identification comprises identifying the operational mode the DSL system was in when the data parameter was last updated, the operational mode comprising at least one of the following: diagnostics; normal initialization; or SHOWTIME.
 5. The method of claim 3 wherein the time reference comprises a point in time defined by at least one of the following: absolute time; relative to one or more phase transitions; or relative to one or more phase-defined events.
 6. The method of claim 1 wherein the operational parameter is a control parameter used to update operation of the DSL system.
 7. The method of claim 6 wherein the timestamp comprises at least one of the following: information regarding whether the update will force initialization; information regarding when the update will be enforced and/or implemented; or information regarding any delay between a known time reference and the enforcement and/or implementation of the update.
 8. The method of claim 1 wherein appending the operational parameter comprises associating the timestamp with a name for the operational parameter and a value for the operational parameter.
 9. The method of claim 1 further comprising: grouping a plurality of operational parameters; and appending the timestamp to the plurality of operational parameters.
 10. The method of claim 1 further comprising: defining a plurality of time markers; wherein appending the timestamp to the operational parameter comprises associating one of the plurality of time markers to the operational parameter. 